Qore::ZMQ::ZSocketReq Class Reference

The ZSocketReq class implements a ZeroMQ REQ socket. More...

Inheritance diagram for Qore::ZMQ::ZSocketReq:

Public Member Methods
	constructor (Qore::ZMQ::ZContext ctx, *string identity, string endpoint)
	constructs a REQ zsocket with an explicit identity and endpoint More...
	constructor (Qore::ZMQ::ZContext ctx)
	constructs an unconnected REQ zsocket with a default system-assigned identity More...
Public Member Methods inherited from Qore::ZMQ::ZSocket
nothing	attach (*string endpoints, bool do_bind=False)
	Attaches the socket to zero or more endpoints. More...
int	bind (string format,...)
	Bind the ZSocket to a formatted endpoint. More...
nothing	connect (string format,...)
	Connects the socket to a formatted endpoint. More...
	copy ()
	Throws an exception; copying ZSocket objects is not currently supported. More...
nothing	disconnect (string format,...)
	Disconnects the socket from a formatted endpoint. More...
*string	endpoint ()
	Returns the last bound endpoint, if any or nothing if not. More...
*string	getIdentity ()
	retrieves the socket identity string More...
auto	getOption (int opt, int bufsize=100)
	Retrieves the value of the given socket option. More...
nothing	monitor (int events, string format,...)
	Creates a bound PAIR socket on the given endpoint which will send the specified events to a single client. More...
ZFrame	recvFrame ()
	Receives a frame from the socket. More...
ZMsg	recvMsg ()
	Receives a message from the socket. More...
nothing	send (Qore::ZMQ::ZMsg msg)
	Sends the given message over the socket; the message is consumed by this call. More...
nothing	send (Qore::ZMQ::ZFrame frame, int flags=0)
	Sends the given frame over the socket; the frame is consumed by this call unless Qore::ZMQ::ZFRAME_REUSE is used in the flags argument. More...
nothing	send (data val,...)
	Sends one or more strings or binary data objects over the socket. More...
nothing	send ()
	Sends a zero-length message over the socket. More...
nothing	setIdentity (string id)
	Sets the socket identity string. More...
	setOption (int opt, int value)
	Sets the given socket option to the given value. More...
	setOption (int opt, bool value)
	Sets the given socket option to the given value. More...
	setOption (int opt, data value)
	Sets the given socket option to the given value. More...
nothing	setRecvHighWaterMark (int value)
	Sets the receive high water mark. More...
nothing	setRecvTimeout (timeout timeout_ms)
	Sets the receive timeout in milliseconds. More...
nothing	setSendTimeout (timeout timeout_ms)
	Sets the send timeout in milliseconds. More...
nothing	setTimeout (timeout timeout_ms)
	Sets the send and receive timeout in milliseconds. More...
string	type ()
	Returns the socket type as a string. More...
nothing	unbind (string format,...)
	Unbinds the socket from a formatted endpoint. More...
nothing	waitRead (timeout timeout_ms)
	Waits for data to read on the socket; if data does not arrive before the timeout expires, a ZSOCKET-TIMEOUT-ERROR exception is thrown. More...
nothing	waitWrite (timeout timeout_ms)
	Waits for data to be written on the socket; if data is not sent before the timeout expires, a ZSOCKET-TIMEOUT-ERROR exception is thrown. More...

Additional Inherited Members
Static Public Member Methods inherited from Qore::ZMQ::ZSocket
static list< hash< ZmqPollInfo > >	poll (list< hash< ZmqPollInfo >> items, timeout timeout_ms)
	polls multiple sockets and returns all sockets with events More...
static nothing	proxy (ZSocket frontend, ZSocket backend, *ZSocket capture)
	starts the built-in ZeroMQ proxy to connect messages between two sockets More...

Detailed Description

The ZSocketReq class implements a ZeroMQ REQ socket.

Restrictions:

Qore::PO_NO_NETWORK

Overview

A socket of type REQ is used by a client to send requests to and receive replies from a service. This socket type allows only an alternating sequence of ZSocket::send*() and subsequent ZSocket::recv*() calls. Each request sent is round-robined among all services, and each reply received is matched with the last issued request.

If no services are available, then any send operation on the socket shall block until at least one service becomes available. The REQ socket shall not discard messages.

Summary of REQ characteristics

Property	Value
Compatible peer sockets	REP, ROUTER
Direction	Bidirectional
Send/receive pattern	Send, Receive, Send, Receive, ...
Outgoing routing strategy	Round-robin
Incoming routing strategy	Last peer
Action in mute state	Block

Note

• This class is not designed to be accessed from multiple threads; it was created without locking for fast and efficient use when used from a single thread. For methods that would be unsafe to use in another thread, any use of such methods in threads other than the thread where the constructor was called will cause a ZSOCKET-THREAD-ERROR to be thrown.
• It is recommended to use an identity with REQ sockets

Member Function Documentation

constructor() [1/2]

Qore::ZMQ::ZSocketReq::constructor

(

Qore::ZMQ::ZContext

ctx

)

constructs an unconnected REQ zsocket with a default system-assigned identity

Example

# create an unconnected REQ socket
ZSocketReq req(zctx);
# set the req's identity value explicitly before connecting
req.setIdentity(ReqIdentity);
req.connect("tcp://127.0.0.1:" + port);

Parameters

ctx	the context for the socket

Exceptions

ZSOCKET-CONSTRUCTOR-ERROR

this exception is thrown if there is any error creating the socket

Note

It is recommended to use an identity with REQ sockets

constructor() [2/2]

Qore::ZMQ::ZSocketReq::constructor	(	Qore::ZMQ::ZContext	ctx,
		*string	identity,
		string	endpoint
	)

constructs a REQ zsocket with an explicit identity and endpoint

Example

ZSocketReq sock(ctx, "my-identity", "tcp://127.0.0.1:8001");

Parameters

ctx	the context for the socket
identity	the identity value for the socket; a missing or empty value here results in the default identity being assigned
endpoint	the endpoint for the socket; the default action is connect

Exceptions

ZSOCKET-CONSTRUCTOR-ERROR	this exception is thrown if there is any error creating the socket
ZSOCKET-CONNECT-ERROR	this exception is thrown if there is any error connecting the socket

Note

It is recommended to use an identity with REQ sockets

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The documentation for this class was generated from the following file:

• QC_ZSocketReq.dox.h